There have conventionally been proposed techniques for receiving, via a touch panel, a mouse, or the like, an instruction entry that designates, by means of two coordinate values (typically, x-coordinate and y-coordinate values), the position of a point within a predetermined two-dimensional region, and processing the entered coordinate values. For example, the literature identified below discloses one such technique.
Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. 2003-114760
[Patent Literature 1] discloses a technique for moving a mouse pointer, which enables precise moves of the pointer by controlling it to move by a travel distance per unit operation amount that is shorter than a travel distance per a unit operation amount.
Meanwhile, techniques for drawing a curve of any kind on a screen by an entry of coordinate values via a touch panel or a mouse are also widely used.
Furthermore, it is also a widespread practice to plot temporal changes of a stock price or body weight by indicating time on the horizontal axis (x axis) and the value at each point of time on the vertical axis (y axis). The shape of the line that represents the graph is formed by each point to make the line being designated by a first coordinate value and a second coordinate value (in the present example, an x-coordinate value and a y-coordinate value, respectively), with a unique second coordinate value y determined for each first coordinate value x as in a form of an explicit function such as y=f(x).